Three convicted heroin dealers from Baltimore are headed back to court for allegedly throwing punches and elbows at federal agents during a drug trial last year.

Brandon Wilson, 24, Taurus Tillman, 29, and John Harrison, 28, appeared in U.S. District Court in Baltimore Friday, where each pleaded not guilty to assaulting a federal officer.

Prosecutors say Harrison punched and elbowed a U.S. Marshal while the prisoner was being escorted from the courtroom during his drug trial. Tillman tried to help Harrison and began “vigorously punching” another marshal in the head, prosecutors wrote in charging documents.

In a separate encounter, Wilson allegedly beat two jailhouse guards. Prosecutors say he threw punches at two corrections officers who were taking him to court.

Each man has asked for a jury trial. Their trial dates are not yet scheduled. They face maximum sentences of eight years in prison each and a $250,000 fine.

Meanwhile, they remain locked up awaiting sentencing for their drug convictions. The five-week drug case was among the biggest trials in Baltimore last year, with prosecutors trying eight men for their roles in a murderous West Baltimore drew crew known as “Trained to Go.” Police called the alleged ringleader, Montana Barronette, 23, the city’s “No. 1 trigger puller.”

Federal authorities charged the men with selling heroin around Sandtown-Winchester, and serving as guns for hire. A jury convicted them all of drug charges.

In addition, the jury found Barronette had a hand in seven murders. Jurors found Harrison guilty of participating in four of those murders and another killing.

The trial proceeded with increased security measures. In a break from routine, the marshals left Harrison handcuffed during the proceedings. Midway through the trial, they began searching the shoes of all spectators. Officials declined to say what caused them to stiffen security measures.

City leaders celebrated the convictions of the drug crew. The eight men all face life in federal prison.

They are scheduled for sentencing hearings through April, with Barronette first on Feb. 15.